Metro officials took the first step yesterday toward expanding the hours that bicycles are allowed on trains.

Bikes currently are permitted only on the last car of the train, after 7 p.m. weeknights and all weekend. Metro board members voted to allow bicycles on trains between 10 a.m. and 2 p.m. weekdays for a six-month trial beginning Aug. 1.

The more liberal policy reflects the influence of General Manager Lawrence G. Reuter. Previous Metro general managers have been cool to the idea of extending subway access to bicyclists. Reuter came to Metro from the San Jose transit agency, which allows bicycles on trolleys and some buses for most of the day.

If the trial is successful, Reuter said, he may ask the board to extend the hours beyond midday. The Washington Area Bicyclist Association has asked transit officials to expand the bike-on-rail program to include 5:30 a.m. to 7 a.m. and 9:30 a.m. to 3 p.m.

"This really is the first step" toward longer hours, Reuter said. "We want to do this in a phased approach."

Among other big-city subway systems, only Atlanta allows bikes on trains all day. Several other systems have more liberal hours than Metro.

Bicyclists planning to take their bikes on Metro still must obtain permits at Metro headquarters and some transit stores.

Increasing the time bicyclists are allowed on trains may not go over well with some riders, transit officials acknowledged. Some people don't like sharing the train with a bicycle. The machines can get grease on the carpet. And some bicyclists are aggressive.

"A lot of people aren't bike fans, especially if you get a rude one who believes it's their constitutional right to ride the train," Reuter said. "That's why we need an education program" for bicyclists and other Metro riders to explain the program.

Only two bicycles will be allowed on the train's last car, although officials said it would be hard to enforce that policy.

"It very much depends on self-policing, and the bicycle association is good at that," Reuter said.

Jim McCarthy, who spearheaded the campaign for expanded hours on behalf of the bicycle association, noted that in its 14 years, the program has had few complaints.

"The major message here is the kind of system we're working toward, one that's rider-friendly so people don't have to take their cars everywhere," McCarthy said. "We understand there would be some problems allowing bikes on trains during the rush hour, particularly in the peak direction, and we didn't ask for that."